Synthroid Uses, Dosage & Side Effects

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Consumption of certain foods may affect SYNTHROID absorption thereby necessitating adjustments in dosing see DOSAGE AND ADMINISTRATION. Soybean flour, cottonseed meal, walnuts, and dietary fiber may bind and decrease the absorption of SYNTHROID from the gastrointestinal tract.

Side Effects for Synthroid

Addition of SYNTHROID therapy in patients with diabetes mellitus may worsen glycemic control and result in increased antidiabetic agent or insulin requirements. Carefully monitor glycemic control, especially when thyroid therapy is started, changed, or discontinued see WARNINGS AND PRECAUTIONS. Patients need to feel comfortable to alert me of any changes in their status in terms of their symptoms. But also specific medical changes that may indicate there may be a need for a dose change or something that could have affected their thyroid hormone levels. This is important as 32% of patients who think they are on SYNTHROID are actually not given this because substitutions are made at the pharmacy.

Absorption of orally administered T4 from the gastrointestinal tract ranges from 40% to 80%. The majority of the SYNTHROID dose is absorbed from the jejunum and upper ileum. The relative bioavailability of SYNTHROID tablets, compared to an equal nominal dose of oral levothyroxine sodium solution, is approximately 93%. T4 absorption is increased by fasting, and decreased in malabsorption syndromes and by certain foods such as soybeans.

Some key points that I discuss with the patients during appointments are, one, is synthroid rashes that this is an open conversation. A levothyroxine product that is not therapeutically equivalent with SYNTHROID might not have the exact same effect on the patient’s TSH as SYNTHROID. The FDA has determined that certain levothyroxine products are interchangeable.

• RxList does not provide medical advice, diagnosis or treatment.
• Indeed, serum TSH levels were lower under the oral solution compared with the tablet both in the replacement group (1.7 mU/l ± 1.0 vs. 5.4 mU/l ± 4.3) and in the TSH-suppressive group (0.1 mU/l ± 0.3 vs. 2.1 mU/l ± 2.7).
• By visiting Synthroid.com, patients can access additional support and resources to understand and manage their hypothyroidism.

Clinical Pharmacology for Synthroid

Closely monitor coagulation tests to permit appropriate and timely dosage adjustments. For adult patients with primary hypothyroidism, titrate until the patient is clinically euthyroid and the serum TSH returns to normal see Recommended Dosage And Titration. There are certain populations where we pay closer attention to thyroid medication dosing. Another group is those that have underlying cardiac disease or are at risk for atrial fibrillation. And a third is those that have severe, long-standing hypothyroidism. The signs and symptoms of overdosage are those of hyperthyroidism see WARNINGS AND PRECAUTIONS and Adverse Reactions.

For additional information, I direct them to the SYNTHROID website where they can go to the “Starting on SYNTHROID” tab to get that further information they may desire. Careful titration of medication and monitoring is required in that setting.

The higher affinity of both TBG and TBPA for T4 partially explains the higher serum levels, slower metabolic clearance, and longer half-life of T4 compared to T3. Protein-bound thyroid hormones exist in reverse equilibrium with small amounts of free hormone. Many drugs and physiologic conditions affect the binding of thyroid hormones to serum proteins see DRUG INTERACTIONS.

SUPPORT FOR PATIENTS

Use the serum free-T4 level to titrate SYNTHROID dosing until the patient is clinically euthyroid and the serum free-T4 level is restored to the upper half of the normal range see Recommended Dosage And Titration. The contradictory findings mentioned may result from the limited size of the cohorts analyzed as well as differences in subjects enrolled (patients vs. healthy volunteers). The aim of this study was to assess the effect of concomitant use of levothyroxine (LT4) and proton pump inhibitors (PPIs) on thyroid-stimulating hormone (TSH) levels in patients with primary hypothyroidism. Personally, I have had experiences where I have written for brand-name SYNTHROID and the patients have been dispensed generic levothyroxine or even another branded levothyroxine product.

Do not administer in foods that decrease absorption of SYNTHROID, such as soybean-based infant formula see DRUG INTERACTIONS. Many drugs can inhibit Synthroid’s adsorption by the body; other medications may increase or decrease its effectiveness once it is adsorbed. Providing a complete list of medications to the doctor will help with getting the correct dose established for each individual patient. Following assessment and application of eligibility criteria, seven studies were included. There was a considerable heterogeneity among the included studies in design, sample size, inclusion and exclusion criteria, treatment regimen, and baseline demographics. Each of the included studies showed an increase in TSH levels following LT4 and PPI consumption, and in the majority of these, the increase was statistically significant.

Stop biotin and biotin-containing supplements for at least 2 days before assessing TSH and/or T4 levels see DRUG INTERACTIONS. To minimize the risk of hyperactivity, start at one-fourth the recommended full replacement dosage, and increase on a weekly basis by one-fourth the full recommended replacement dosage until the full recommended replacement dosage is reached. Synthroid is also used in patients who need surgery and radioiodine therapy to manage a type of thyroid cancer called well-differentiated thyroid cancer.